This invention relates to fire retardant composites and fire-resistant mattresses. In particular, it relates to fire retardant composites capable of withstanding significant tensile forces and to fire resistant mattresses made using such composites.
Each year thousands of people die in home and institutional fires that started in or were fueled by mattresses. The traditional mattresses contain highly flammable materials that are necessary to provide the required comfort for the users. Most mattresses include a layer of ticking material which is generally flammable. Once the bedding on the mattress catches on fire, the flames ignite the ticking. Within a few minutes, the surface of the mattress is ablaze. The fire then spreads to the cushion layer which is generally made of either polyurethane foam or cotton. Such cushion layers are readily ignitable and an excellent fuel for the fire.
The springs of the traditional mattresses are in normal use held under compression by the materials that enclose them. Once the fire begins consuming these materials, the springs burst the mattress open thereby fully exposing the flammable materials inside the mattress to the fire. This accelerates the fire. The heat from the fire and combustion of flammable materials produce toxic gases which accumulate in the room. As the temperature in the room rises, these gases ignite producing a phenomenon called "flashover." During "flashover", the entire space of the room becomes engulfed in flames. The temperature of the room in which the mattress is located can reach 1300.degree. C. or higher. If the door to the room in which the mattress is located is open, the flames follow the exiting gases creating a moving wall of fire.
Since traditional mattresses are generally one of the chief sources of fuel for a fire and since once ignited they burn rapidly and emit toxic and flammable gases, the damages, injuries and loss of life resulting from fires could be significantly reduced if mattresses were substantially fire proofed.
Attempts have been made to produce commercially acceptable fireproofed mattresses and to use fire retardant materials in their construction to prevent the spread of fire. None of these attempts have been entirely satisfactory.
For example, U.S. Pat. No. 3,512,192 (Simon) discloses a mattress made of a multilayer material. On the outside, the mattress is covered with a chemically treated ticking with no insulating value. Adjacent to the ticking is a layer of polyurethane foam and to the inside of the polyurethane foam is a layer of fiberglass matting. The fiberglass matting can be replaced by an asbestos pad. To the inside of the fiberglass matting or asbestos pad is another layer of polyurethane foam. See also Column 2, lines 41-45. The problem with the approach disclosed in the Simon patent is that the chemically treated ticking has practically no insulating value and therefore it cannot adequately protect the materials it encloses from the fire. Once the fire spreads to the polyurethane layer, it is fueled just like in the traditional mattresses causing a conflagration.
Additionally, the use of the fiberglass matting is impractical even under the polyurethane foam because the fiberglass fibers gradually break off and eventually penetrate the surface of the mattress causing serious discomfort and irritation to the user. The minute fiberglass fibers can also become embedded in the linen. Since they cannot be removed from the linen by laundering, the contaminated linen has to be replaced in order to avoid irritation or even allergic reaction of the user.
U.S. Pat. No. 3,670,348 (Irwin) discloses the use of a fiberglass pad inside the ticking to enclose the combustible portion of the mattress. The problem with this approach is that the fiberglass pad is not a durable and resilient surface. Therefore, such mattresses lack the soft feel of traditional mattresses. Moreover, during use, the minute fibers of the fiberglass pad break off and penetrate the surface of the mattress causing discomfort and irritation to the user as described in connection with the Simon patent. This problem is more serious in mattresses disclosed by the Irvine patent than in those disclosed by the Simon patent because the fiberglass pad is adjacent to the thin outside ticking layer which is easily penetrated.
U.S. Pat. No. 3,818,521 (Richards) discloses the use of a heat conducting metallic foil between the ticking and the padding layers. The foil carries away heat that is applied to a small area of the mattress and thereby prevents the ticking from bursting into flames. This approach suffers from several disadvantages. It works only if the heat source is small in intensity and localized. For example, the Richards mattress will help prevent fire if a burning cigarette or a match is placed thereon. This approach does not work, however, in situations where the source of fire is not highly localized. If other parts of the room are on fire, the metallic foil is ineffective to prevent mattress fire.
U.S. Pat. No. 4,092,752 (Dougan) discloses the use of a layer of flame retarded flexible polyurethane foam and optionally an outer layer of flexible polymide foam to enclose the flammable parts of the mattress. Similarly, the paper entitled Flammability Characteristics of Healthcare Mattresses by Anolick et al, presented at the August 1977 American Hospital Association's Annual Convention, discloses mattresses that include VONAR.TM. interliners, inside the ticking layer, completely enclosing polyurethane foam. Such mattresses are reported to significantly improve the controllability of fires. However, once charred, VONAR.TM. lacks the strength to keep the mattress intact. Accordingly, at elevated temperatures, such mattresses burst open thereby exposing to the fire the flammable parts. The entire mattress then explodes into flames. The ticking used in the mattresses disclosed by the Anolick article has no insulating value and therefore does not provide a barrier to fires.
More recently, Golding Industries, Inc. proposed mattresses having flame-resistant ticking marketed under the trademark SANDEL. This approach suffers from several disadvantages. The first disadvantage is its cost. The SANDEL ticking includes fiberglass fibers. But in order to make the ticking soft and flexible enough to be acceptable to the user, very fine fibers must be used. Such ticking is significantly more expensive than the conventional ticking.
Secondly, the fiberglass fibers break off during use and cause irritation and allergic reactions to at least some users. The fibers are so minute that they cannot be removed from the linen by laundering. Accordingly, once the ticking starts breaking, the linen then on the mattress has to be replaced.
Finally, since the SANDEL ticking does not create a heat shield, the heat from the fire can lead to outgasing, i.e., the release of toxic and flammable gases from the materials inside the mattress.
There is, therefore, a long felt and still unsatisfied need for a mattress that does not ignite and burst into flames either immediately upon exposure to a fire or upon exposure to elevated temperatures normally encountered in household or institutional room fires but which offers all the comfort properties of a traditional mattress, including softness and conformance to the body contours of the user.
Thus, one object of the present invention is to provide an improved mattress that satisfies the above stated need.
Another object of the present invention is to provide a composite useful in the construction of said improved mattress and a process for making such composite.
A further object of the present invention is to provide an improved fire resistant mattress which lasts at least as long as the conventional mattresses and retains its fire resistant properties throughout its useful life.
Still another object of the present invention is to provide an improved mattress whose outer layer has an excellent surface feel and softness and does not cause skin irritation to the users.
A still further object of the present invention is to provide an improved fire-resistant mattress and fire-retardant composites for use in such mattress, which are inexpensive and have a long, useful life.
Still another object of the present invention is to provide a mattress which generates significantly less smoke and toxic gases than traditional mattresses when exposed to a fire.
Other objects of the present invention will become apparent to those skilled in the art upon studying this disclosure.